Device and method for treatment of atrioventricular regurgitation

ABSTRACT

A device for treatment of atrioventricular regurgitation comprises a suturing means. The suturing means has such dimensions as to be introducible, via blood vessels leading to the heart, to two leaflets of the atrioventricular valve between an atrium and a corresponding ventricle of the heart. Further, the suturing means is designed for binding together the two leaflets in a position along the free edges of the leaflets. As a result, the closing of the valve is improved.  
     A method of using the device comprises the steps of inserting the suturing means into a catheter, introducing the catheter to the heart, so as to position a distal end of the catheter close to two leaflets of an atrioventricular valve, capturing the free edges of the two leaflets with the suturing means in its open state, binding together the two leaflets by transition of the suturing means into its closed state, and retracting the catheter from the heart.

BACKGROUND OF THE INVENTION

[0001] The invention relates to a device for treatment ofatrioventricular regurgitation and a method for treatment ofatrioventricular regurgitation using said device.

[0002] The heart has two atrioventricular valves, the mitral valve,which is situated between the left atrium and the left ventricle, andthe tricuspid valve situated between the right atrium and the rightventricle. The tricuspid valve has three leaflets, two of which are muchbigger than the third. These two bigger leaflets could be considered tocorrespond to the two leaflets of the mitral valve. Therefore, only themitral valve will hereinafter be discussed although correspondingdiscussions could apply to the tricuspid valve.

[0003] Mitral regurgitation is the medical name of a problem that occursin the heart. A person that suffers from mitral regurgitation has amitral insufficiency, i.e. the mitral valve between the left atrium andthe left ventricle cannot close entirely. Thus, when the ventricle iscontracted in order to pump out blood through the aorta, some bloodleaks back into the atrium instead. This will lead to a reducedfunctionality of the left ventricle and subsequently to heartinsufficiency, which is a mortal disease.

[0004] Mitral insufficiency can result from, for example, ischemicdisease, degenerative disease of the mitral apparatus, rheumatic fever,endocarditis, congenital heart disease and cardiomyopathy. The fourmajor structural components of the mitral valve are the annulus, the twoleaflets, the chordae and the papillary muscles. Any one or all of thesein different combinations may be injured and create insufficiency.

[0005] At present mitral regurgitation is treated by open-heart surgery.This is a major operation and requires the use of total cardiopulmonaryby-pass, aortic cross clamping and cardioplegic arrest. To certaingroups of patients this is particularly hazardous and there is anapparent risk of not surviving the operation.

[0006] The treatment consists of either mitral valve replacement orrepair. Replacement can be performed with either mechanical orbiological valves.

[0007] The mechanical valve carries the risk of thromboembolism andrequires anticoagulation, with all its potential hazards, whereasbiological prostheses suffer from limited durability. Another hazard inconnection with replacement is the risk of endocarditis. These risks andother valve related complications are greatly diminished with valverepair.

[0008] The four basic techniques of repair include the use of anannuloplasty ring, quadrangular segmental resection of diseasedposterior leaflet, shortening of elongated chordae, and transposition ofposterior leaflet chordae to the anterior leaflet. The techniques ofmitral valve repair rely on decreasing valve area to increase leafletapposition, but fail to address subvalvular dysfunction. Mitralinsufficiency caused by prolapse of the anterior leaflet, posteriorleaflet with calcified annulus, or prolapse of both leaflets constitutesa more demanding challenge to repair.

[0009] In 1995 Alfieri et al introduced modifications in the operativetechnique that allow a more expeditious and reproducible procedure thanthe traditional of greater complexity. This is achieved by simplyanchoring the prolapsing free edge of the leaflet to the facing edge ofthe other leaflet (edge-to-edge technique), thus creating a doubleorifice of the mitral valve. The hemodynamic behavior of a doubleorifice mitral valve does not differ from that of a physiological valveof the same total area. Pressure drops and flow velocity across thevalve are not influenced by the configuration of the valve.

[0010] Some efficient methods of treating mitral insufficiency exist asshown above, but all of them require open-heart surgery. Since manypatients with mitral regurgitation are elderly or have a poor leftventricular function, they would benefit from a less invasive procedurethat does not involve the use of cardiopulmonary by-pass as required byconventional techniques.

SUMMARY OF THE INVENTION

[0011] The object of the invention is to provide a device and a methodfor treatment of atrioventricular regurgitation that will be applicableto a beating heart.

[0012] This is accomplished by a device according to claim 1 and amethod according to claim 15. Preferred embodiments of the device andthe method are defined in the dependent claims 2-14 and 16-23,respectively.

[0013] Thus, a device for treatment of atrioventricular regurgitationcomprises a suturing means having such dimensions as to be introducible,via blood vessels leading to the heart, to two leaflets of anatrioventricular valve between an atrium and a corresponding ventricleof the heart and being designed for binding together the two leaflets ina position along the free edges of the leaflets, whereby the closing ofthe atrioventricular valve is improved.

[0014] Preferably, the atrioventricular valve is the mitral valvebetween the left atrium and the left ventricle of the heart.

[0015] Diseases to the atrioventricular valves are much more common inthe mitral valve than in the tricuspid valve. Therefore the focus of theinvention is on the treatment of the mitral valve although treatment ofthe tricuspid valve could work equally well using the device.

[0016] The suturing means is preferably transitional between two states,being open in a first state and substantially closed in a second state.

[0017] This makes the suturing means capable of reaching the free edgesof the mitral leaflets in the first state and of bringing them closer toeach other when transitioned into the second state.

[0018] In a preferred embodiment, the suturing means comprises a clip.

[0019] Preferably, the clip has two arms pivotally connected to eachother at a first end thereof, the arms forming a V in the first state ofthe clip and being substantially parallel in the second state of theclip.

[0020] Consequently, the arms of the clip can capture both mitralleaflets in the first state and bring them closer together in the secondstate.

[0021] Desirably, the arms of the clip have second, free ends benttowards each other so that these ends of the arms in the second state ofthe clip are brought proximal to each other.

[0022] This means that the mitral leaflets can be brought in closeproximity to create a suture as the ends of the arms capturing themitral leaflets in the second state of the clip are brought proximal toeach other.

[0023] Further, each second end of the arms is preferably sharp.

[0024] As a result, the clip can easily capture the mitral leaflets andare capable of gripping the leaflets between its arms.

[0025] Suitably, the clip has two pairs of arms connected to each otherby two crossbars near the connected first ends of the arms.

[0026] This means that the clip can get a good and lasting grip on themitral leaflets.

[0027] Preferably, the device comprises a catheter for introduction ofthe clip via the blood vessels into the heart, said catheter having anoutermost sheet covering the clip and being retractable therefrom.

[0028] This allows the clip to easily be introduced into the heart andthere be uncovered for application to the mitral valve.

[0029] In one embodiment the catheter has a rod for holding the clipsubstantially in the open state within the outermost sheet and anapplicator for pushing the clip off the rod for transition thereof intothe closed state when the outermost sheet is retracted from the clip.

[0030] This is desirable for the application of the suturing means, asthe transition between the two states of the suturing means can becontrolled for capturing and suturing of the mitral leaflets.

[0031] In another embodiment the catheter has a rod for holding the clipsubstantially in the open state within the outermost sheet, said rodalso having a puncturing means at a distal tip thereof.

[0032] This means that the catheter can be introduced via a vein sincethe puncturing means can be used to puncture the interatrial septum soas to enable the device to be brought into the left atrium from theright atrium.

[0033] Preferably, the suturing means consists of a memory material suchas Nitinol.

[0034] As a result, the suturing means can easily be made to transformfrom its first state to its second and thereafter maintain its secondstate.

[0035] According to the present invention, the method for treatment ofatrioventricular regurgitation comprises the steps of providing asuturing means having an open state and a closed state; inserting thesuturing means into the distal end of a catheter; introducing thecatheter via blood vessels leading to the heart, so as to position thedistal end of the catheter close to the free edges of two leaflets of anatrioventricular valve between an atrium and a corresponding ventricleof the heart; capturing the free edges of the two leaflets with thesuturing means in its open state; binding together the two leaflets bytransition of the suturing means into its closed state; and retractingthe catheter from the heart while leaving the suturing means fixed onthe two leaflets.

[0036] Preferably, the atrioventricular valve is the mitral valvebetween the left atrium and the left ventricle.

[0037] Preferably, the suturing means is covered with a protective sheetof the catheter when introduced into the distal end thereof anduncovered by retraction of the protective sheet when positioned close tothe free edges of the two leaflets of the atrioventricular valve.

[0038] Consequently, the suturing means can be introduced into the heartin a convenient way and be exposed in the ventricle.

[0039] In a mitral valve embodiment of the invention the catheter isintroduced into the brachial or femoral artery and is passed retrogradeto the blood flow through the aorta to the left ventricle.

[0040] In another mitral valve embodiment the catheter is introducedinto a vein and passed up to the heart via the vein. The catheter couldbe introduced through any suitable vein, such as the femoral, jugular orsubclavian veins. In this embodiment, the catheter preferably has apuncturing means on a distal tip thereof, such that the interatrialseptum may be punctured by said puncturing means and the catheter beintroduced through the septum to the left atrium and then passed to theleft ventricle.

[0041] This means that the catheter may be introduced through thefemoral vein since a passage from the right side of the heart to theleft side is achievable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The invention will be better understood by means of the followingdescription of preferred embodiments referring to the accompanyingdrawings, in which

[0043]FIG. 1 is a partially sectional view of a heart having a suturingmeans applied on the mitral valve according to the present invention;

[0044]FIG. 2 is a perspective view of a suturing means according to thepresent invention;

[0045]FIG. 3 is a sectional view of a catheter carrying a suturing meansaccording to one embodiment of the invention;

[0046]FIG. 4 is a perspective view of the catheter in FIG. 3 carrying asuturing means that has been unsheathed;

[0047]FIG. 5 shows schematically how a device according to the inventioncan be inserted through an artery into the left ventricle of the heart;

[0048]FIG. 6 is a sectional view of a catheter carrying a suturing meansaccording to another embodiment of the present invention;

[0049]FIG. 7 is a perspective view of the catheter in FIG. 6 carrying asuturing means that has been unsheathed according to another embodimentof the invention; and

[0050]FIG. 8 shows schematically how a device according to the inventioncan be inserted through a vein into the left ventricle of the heart.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] The device will now be described with reference to its use on amitral valve. However, it is obvious that the device could also be usedon the two biggest leaflets of the tricuspid valve.

[0052]FIG. 1 shows a heart 1. The left side of the heart 1 is shown insection. A clip constituting a suturing means 2 is applied to the freeedges of the mitral valve 3 keeping the mitral leaflets 4, 5 together ina connection point so as to create a double orifice, one orifice on eachside of the connection point, thus allowing the leaflets 4, 5 to closecompletely.

[0053] In the following there will be described a device and a methodfor creating a double orifice in the mitral valve 3 of a beating heart1.

[0054] Referring now to FIG. 2, an enlargement of the suturing means 2is showed. The suturing means 2 being a clip consists of two pairs 6, 7of arms 8-9 and 10-11. The arms 8-9 and 10-11 in the pairs are connectedin one end 14, 15 and thus are formed in one piece. In their other endthe arms 8-9 and 10-11 are bent towards each other in a bent portion 16.The bent portions 16 are terminated with a sharp tip 17 so as to be ableto engage and grab the mitral leaflets 4, 5.

[0055] The clip 2 has two parallel crossbars 12, 13 that each connectone arm 8, 9 in one pair 6 to one arm 10, 11 in the other pair 7. Thecrossbars 12, 13 are equally long and are connected to the arms 8-9 and10-11 at equal distance from the connections 14, 15. The pairs 6, 7 ofarms are thus kept parallel by the crossbars 12, 13. The crossbars 12,13 are attached to the arms 8-9 and 10-11 near the connection ends 14,15.

[0056] The clip 2 is made of a memory metal, such as Nitinol, and inFIG. 2 it is shown in a second state where the arms 8-9 and 10-11 in thepairs are parallel and the bent portions 16 in their ends are brought inclose proximity to each other. The memory material of the clip 2 biasesthe clip 2 towards its second, closed state. In a first state, the arms8-9 and 10-11 in the pairs are opened, forming a V, as the angle intheir connections 14, 15 is increased. The clip 2 is capable of graspingthe mitral leaflets 4, 5 at their free edges and bind the edges togetherby capturing the leaflets 4, 5 in the first state of the clip 2 andkeeping them together in the second state of the clip 2, where the armsare closed and parallel.

[0057] The clip 2 is inserted into a beating heart 1 by using acatheter. Referring to FIGS. 3 and 4, a first embodiment of a catheter18 will be described. In its innermost part the catheter 18 has asupportive rod 19 that is slidable in a hollow applicator 20. In itsoutermost part the catheter 18 has a protective sheet 21 that also isslidable upon the applicator 20.

[0058] The clip 2 is attached in a distal end of the catheter to theapplicator 20. The attachment is made in the connections 14, 15 of thearms 8-9 and 10-11 in the pairs. The supportive rod 19 can be extendedout of the applicator 20 and be held between the two crossbars 12, 13 ofthe clip 2. The supportive rod 19 does in this condition hold the arms8-9 and 10-11 in the pairs of the clip 2 apart, keeping the clip 2 inits first, open state. The protective sheet 21 can be pushed over theclip 2 to make the catheter 18 easier to introduce into the heart 1 andkeep the arms 8-9 and 10-11 in the pairs parallel from the crossbars 12,13 towards the bent portions 16 as shown in FIG. 3, the clip 2 stillbeing held substantially in the open state. In this way the clip 2 doesnot get stuck as it is passed into the heart 1.

[0059] In FIG. 4 the protective sheet 21 is drawn back along theapplicator 20, thus uncovering the clip 2 and allowing the clip 2 totake the form of its first state. The clip 2 can then be transformedinto its second state by retracting the supportive rod 19 that keeps thecrossbars 12, 13 of the clip 2 apart.

[0060] A second alternative embodiment of the catheter 18′ is shown inFIGS. 6 and 7. The catheter 18′ comprises a supportive rod 19′ that inthe distal end of the catheter can be entered and held between the twocrossbars 12, 13 of the clip 2 and extend past the connection ends 14,15 of the arms 8-9 and 10-11 in the pairs. The supportive rod 19′ doesin this condition hold the arms 8-9 and 10-11 in the pairs of the clip 2apart, thus keeping the clip 2 in its first state.

[0061] In its distal end the supportive rod 19′ has a needle 22 that canbe used to puncture the interatrial septum. The catheter 18′ has anoutermost protective sheet 21′ that is slidable upon the supportive rod19′. When the catheter 18′ is inserted into the heart 1, the protectivesheet 21′ covers the clip 2 keeping the arms 8-9 and 10-11 in the pairsparallel from the crossbars 12, 13 towards the bent portions 16 as shownin FIG. 6 and also covers the needle 22 of the supportive rod 19′.However, the clip 2 is still held substantially in the open state withits free ends 16 apart. As the protective sheet 21′ is drawn back, itfirst uncovers the needle 22 allowing it to puncture the interatrialseptum and then uncovers the clip 2 allowing it to take the form of itsfirst state. The supportive rod 19′ can then be retracted making theclip 2 transform into its second state.

[0062] The catheter 18, 18′ could also have an ultrasound probe toprovide an easy way for visualizing the device inside the heart 1. Thesupportive rod 19, 19′ could be designed to also provide the ultrasoundprobe. Ultrasound could also be used in other ways for visualization,e.g. by inserting an ultrasound probe inside the oesophagus.

[0063] Two alternative methods for inserting the device for treatingmitral regurgitation will be described in the following. The insertionis done into a beating heart and can be performed in local anesthesia.

[0064] Both methods include an introduction of a catheter into theheart. These introductions described below are standard techniquescurrently used for diagnostic left heart catheterization.

[0065] The first method uses the catheter 18 shown in FIGS. 3 and 4.Referring to FIG. 5, the catheter 18 is inserted into the body throughthe brachial or the femoral artery. The catheter 18 is then passedretrograde along the artery into the left ventricle of the heart 1. Theprotective sheet 21 is then retracted as shown in FIG. 4, thusuncovering the clip 2. The clip 2 is now in its first, open state and isused to capture the mitral leaflets 4, 5, preferably in the middle oftheir free edges. The sharp ends 17 of the bent portions 16 of the arms8-11 give a steady grip on the mitral leaflets 4, 5. The supportive rod19 is then retracted, thus allowing the clip 2 to transform into itssecond state. The clip 2 thereby closes and keeps the captured parts ofthe two mitral leaflets 4, 5 together. The clip 2 is now in place tograsp and approximate the free edges of the mitral leaflets 4, 5 by theedge-to-edge technique. A double orifice, one on each side of thesuture, is thus formed. This double orifice can be closed completely bythe mitral valve. Finally, the catheter 18 is retracted from the heart1, leaving the clip 2 forming the double orifice.

[0066] The second method uses the catheter 18′ shown in FIGS. 6 and 7.The catheter 18′ is inserted into the body through the femoral vein. Thecatheter 18′ could be inserted through any other suitable vein, such asthe jugular or the subclavian vein. Referring to FIG. 8, the catheter18′ is passed along the femoral vein into the vena cava and further intothe right atrium. The needle 22 in the distal end of the supportive rod19′ is unsheathed by a retraction of the protective sheet 21′ of thecatheter 18′. The needle 22 is then used to puncture the interatrialseptum to give the catheter 18′ a passage into the left atrium and thenthrough the mitral valve into the left ventricle. When the catheter hasbeen passed into the left ventricle, the protective sheet 21′ isretracted further, whereupon the clip 2 unfolds. The clip 2 is now inits first, open state and the mitral leaflets 4, 5 can be captured inthe same manner as described for the first method. When the supportiverod 19′ is retracted, the clip 2 transforms into its second state, thusclosing and keeping the mitral leaflets 4, 5 together. The clip 2 is nowin place to grasp and approximate the free edges of the mitral leaflets4, 5 by the edge-to-edge technique. As for the first method a doubleorifice that the mitral valve can close completely is created. Finallythe catheter 18′ is retracted completely from the body leaving the clip2 forming the double orifice.

[0067] When treating tricuspid regurgitation the catheter 18′ is usedwithout the needle 22 on the distal end of the supportive rod 19′. Thecatheter 18′ is inserted into the body through a vein, such as thefemoral, jugular or subclavian veins. The catheter 18′ is passed alongthe vein into the right atrium of the heart 1. The catheter 18′ is theninserted through the tricuspid valve into the right ventricle. Here theprotective sheet 21′ is retracted to uncover the clip 2 and the captureof the two biggest leaflets of the tricuspid valve could be performed inthe same manner as described for the mitral valve described above.Finally, the catheter 18′ is retracted leaving the device fixed on twoleaflets of the tricuspid valve.

[0068] Although particular embodiments of the present invention havebeen described, the application is not limited to these embodiments butincludes modifications that are obvious to the skilled man and arecomprised in the scope of the invention as defined in the appendedclaims. For example, it is obvious that different embodiments of clipscan be designed. Modifications of the suturing means are possible innumerous ways without extending beyond the spirit of the invention.

What is claimed is:
 1. A device for treatment of atrioventricularregurgitation in a heart, comprising a suturing means having suchdimensions as to be introducible, via blood vessels leading to theheart, to two leaflets of an atrioventricular valve between an atriumand a corresponding ventricle of the heart and being designed forbinding together the two leaflets in a position along the free edges ofthe leaflets, whereby the closing of the atrioventricular valve isimproved.